Protective apparatus for electric circuits.



I R. L. BAKER.

' PROTECTIVE APPARATUS-FOR ELECTRIC CIRCUITS.

APPLICATION, FILED JAN. 13, 1912.

Patented May 13, 1913.

4 SHEETS-SHEET 1.

R. L. BAKER. PROTECTIVE APPARATUS FOR ELECTRIC moms.

APPLIQlTION FILLED JAN. 13, 1912.

Patented May 13, 1913.

4 SHEETSSHEET 2.

MMM

R. L BAKER. PROTECTIVE APPARATUS FOR ELECTRIC CIRCUITS.

APPLICATION FILED JAN.13,1912.

Patented May 13, 1913.

' 4 SEEETE SHEET 3.

wu lu I v m R. L. BAKER. I PROTECTIVE APPARATUS FOR ELECTRIC CIRCUITS.

APPLICATION FILED JAN.13, 1912.

1,061,894, Patented May 13, 1913.

, 4 SHEETS-SHEET 4.

UNITED STATES PATENT OFFICE.

BOSS LEE BAKER, OF JOPLIN, MISSOURI.

PROTECTIVE APPARATUS FOR ELECTRIC CIRCUITS.

Specification of Letters Patent.

Application filed January 13, 1912. Serial No. 671,053.

To all 'whom it may concern:

Be it known that I, Ross LEE BAKER, a citizen of the United States, residing v at Joplin, in the county of Jasper and State of Missouri, have invented certain new and. useful Improvements in Protective Apparatus for Electric Circuits; and I do hereby declare the following to be a full, clear, and

exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to improvements in protective appliances for electrical circuit apparatus, and more particularly to the type commonly known as plug fuse.

It is the common practice to supply distribution circuits with high tension low amperage current, and to transform the current for particular use, and to protect the various apparatus in circuit it is customary to provide fuses in the conductors leading to the transformers. These fuses are usually sustained by what is commonly known as fuse plugs mounted in fuse blocks and thus protected against the weather, the transformers and blocks being usually mounted on poles and exposed to climatic conditions.

Or the transformers with their fuse plugs.

may be-arranged in manholes or other out of the way places which aremore or less difficult of access. Frequently several transformers are 'bankedjand, with the fuse blocks and plugs now commonly in use, it-

is necessary to withdraw each fuse plug and examine it for ascertaining whether or not its fuse is in good condition so as to determine whether. or not the particular trans former is working. Thus it will be seen than an inspector passing along a roadway must climb each pole on which is mounted a transformer and withdraw both of the fuse plugs to ascertain the condition of the fuses, and whenever there happens to betwo or more transformers banked, two plugs must be withdrawn for each transformer, with the attendant risk and danger to the operator.

The object of the present invention-is essentially to obviate this labor and render it possible to make a reliable inspection at a.

glance, and this object is proposed to be attained in a fuse plug and block adapted particularly for out-of-door application on lines carrying hi h voltage, say in excess of one thousand, but relatively low currents.

With this and further objects in view, as will in part hereinafter become obvious and in part be stated, the invention comprises certain novel constructions, combinations and arrangements of parts as will be herein specified and claimed.

In the accompanying drawings,-Figure Patented May 13, 1913.

1 is an applied view showing a transformer mounted on a pole and provided with pro tective appliances embodying the features of the present invention. Fig. 2 is a diagrammatic view illustrating banked transformers similarly provided. Fig. 3 is a detail, vertical, central section through a fuse block and plug embodying the "features of the present invention. Fig. 4 is a view in side elevation of the fuse plug detached. Figs.

5 and 6 are plan views respectively of the fuse plug and the fuse block. Figs. 7, 8, 9 and 10 are, respectively, fragmentary, vertical sections through the plug illustrating modified embodiments of the signal actuating spring. Fig. 11 is a vertical, central section through a modified form of plug.' Fig. 12 is a similar view of a further modification, the section being taken on line 12-12 of Fig. 13. Fig. 13 is a transverse section taken on line 13-l3 of Fig. 12.1. Fig.

14 is a view similar to Fig. 11 of a further embodiment. Fig. 15 is a plan view thereof. Fig. 16 is a similar view of a still further embodiment. Fig. 17 is a plan view thereof. Fig. 18 is a detail, fragmentary view of a modified form of a portion of the signal plunger. Fig. 19 is a vertical section through a further modified embodiment,

' showing both the fuse block. and plug. Fig.v

20 is a fragmentary, detail view of a fu rther modified embodiment.

In Fig. 1, I have indicated a transformer 1 supplied with current through conductors passing through the fuses of fuse blocks 2, 2, each embodying the features of the present invention.

In Fig. 2, I have illustrated the trans with means for receiving supports after the manner of the well known type of fuse block. Within the block are arranged contact terminals 3, 3, fixed to the block and electrically connected with the binding post 4:, 4, to which the'ends of the conductor 5 are connected. Between the contact termi- 5 nals 3 is the plug receiving opening or space of the block, and the plug 6 is adapted to be introduced thereinto in posit-ion for having the fuse'terminals .7, 7 thereof contact with the terminals 3,3, for closing the circuit through the fuse 8, which connects the terminal 7. Fuse 8, of course, may be I a wire or ribbon of lead or other fusible substance adapted to be ruptured by excessive fluctuations in the 'load prior to' injury to any other apparatus in line. The

ing at' its outer or lower ends a flange 9,

' and a pendent operating knob 10 adapted to be grasped by the fingers of the operator for,

' withdrawing the. plug or thrusting it to place in the block. The body of the plug I grooves 11, 11, in which extends the fuse wire 8, which wire is thus retained against accidental displacement. The plugj6 is formed throughout its length with a central bore, which also extends through the knob 10, and in which is mounted the signal plunger 12, which consists of a shaft ex: tending throughout the length of the plug, and. atv its inner or upper end engaging the fuse wire 8.- The upper end of the plunger 12 may be grooved, as at 12', for receivingthe wire 8 and preventing lateral displacement thereof. The plunger 12 is of a greater length than the lu and 'normally has its lower end projecting low the knob o 10 so as to be clearly exposed to View. The body of the plug is formed with lateral openings 13, 13, adjacent flange 9, and a ;.spri ng 14 extends throughplunger l0 and has its ends projecting through the aper tures 13, The-spring is susceptible of numerous embodiments, but ashshown consists of a semi-ellipticplate spring tensioned to project its middle ortionj upwardly to the position indicated in dotted lines in Fig, 3

- when free. The tension of the spring is such as to insure elevation of the plunger in the instance of rupture of wire 8, but is vnot i such as to efiect injurious stretching of the f 4 leg rests on the materialofthe plug at both wire.

When the plug -6 has been seated in the 1 bloc'k2 with theparts in the position. indii catedin full lines in Fig. 3, current may flow I along conductor 5 and along wire 8, and the .--wire 8 will retain'the plunger 12 inposi- 0 tion-with its lower. end protruded. For con venienceof inspection, I propose to form the lower'end of the plunger 12 of white substance, or to color it white, while the plug itself and the fuse block will be of some other color, as for instance a very dark fuse pIug 6 consists of a tapering body havcolor if formed of porcelain. The plunger is, of course, of non-conducting substance, and the space within the block 2 is of sufiicient area to accommodate the upper portion of the plunger whien projected u'pwardly or to the retracted or signaling position as indicated indotted lines' in Fig. 3. So long as the fuse wire 8 remains intact,

the lower end of the plunger 12 will be protruded, and, therefore, the inspector needs only to observe this fact to be assured that the fuse block is in perfect condition, and if he sees that the plunger has been retracted he will know that the block requires attention, and he is thus relieved of the necessity for climbing poles or getting down into man-holes merely to inspect. When a rup ture has occurred, it is not necessary 'to discard any part of the plug or block, but the operator merely replaces a new fuse wire and returns the plug to its position in the block. The parts are then again in opera tive condition.

In Figs. 7, 8, 92nd 10, I have illustrated InFig. 8, a full elliptic spring 14 is pro vided and extends through an aperture in the plunger, having one of its plates resting against the material of the plug, and the other plate engaging the ing the plunger upwardly.

In. Fig. 9, the spring 14 consists merelyof a spring .wire having a return bend disposed to have one leg of the bend rest against the material of the plug, and the otherlegextending' into an aperture in the plunger and pressing. the plunger upwardly.

-' InFigv 10, the springl l is provided and is very similar in. construction and arrange- 'ment to spring. except that the wire is coiled .at the bend and both legsextend entirelyjthrou'gh the, plunger, so that the lower sides of the plunger.

Obviously,in these several modifications,

plunger for pressthe recesses or apertures in the partswill be 7 varied proportionately to the slze, disposrtion and action of the respective springs. 1 In Fig. 11, 6 is the plug carrying the fuse wire 8 engaged by the signaling plunger 12 operating in the same general way and for the same purpose as the lunger 12, but

difiering therefrom in being ormed ofthree sections consisting of the end sections 15 and rests on a seat formed of material of the plug, and has its upper end engaging the section 16 for pressing the plunger inwardly and upwardly. The stem 17'maybe connected to the end sections in various ways, and I find one convenient method of connection to consist in the use of countersunk screws extending through the end sections and threaded into the ends of the stem.

In Figs. 12 .and 13 I have illustrated-a slight modification from the structure seen in Fig: 11, the same general form of plug 6 and plunger 12 being employed, but the plunger being actuated by, a modified arrangement of the spring. The springin this embodiment is quite similar to the spring seen in Fig. 7, and consists of a spring wire 14 coiled and having one end "embedded in material of the plug,'and the free end.

bent and passed through the stem of the plunger 12 so as tov have pivotal engagement therewith. Spring 14 is tensioned for having its free end press in an upward direction.

In Figs. 14 and 15, I have illustrated quite a material variation in the action of the signaling plunger, which in this embodiment indicates rupture of the fuse wire when projected instead of when retracted. The plug 6 is provided with the usual fuse wire 8, but the inner end of the plugis recessed, as indicated at 19, so that that ortion of the fusewire which crosses the inner end may be subjected to'tension in a downward direction. The plunger 12 consists of a lower section of insulating material, and a stem 20 fixed to and extending from the lower section throughout the remaining length of the plug, the plug being suitably bored for accommodating the stem.

The upper or. inner end of the stem is formed with a-hook 21 which overhangs and engages the wire 8 so as to subject the same to tension by virtue of the weight of the' plunger, which may be sufiicient to alone afiord' assurance ofefiective signaling action on rupture of the wire 8. Or if desired a spring 22 may be coiled about the lower portion of the stem and have one end engage the material of theplug, and the other end ongage the upper end of the lower section of the plunger for pressing the same downwardly.

Obviously, any break in the wire 8 will release the hook 21 and allow the plunger to move downwardly to the dotted line position indicated in Fig. 14, andthus indicate that the fuse has been destroyed. j I In Figs. 16 and .17, I' have indicated a further embodiment, varying only slightly from the structure just described. 1 In these last figures the plug 6 is shown as provided of the plug does not extend throughout the length of the plug, but is of suflicientlength to accommodate the inclo-sed plunger which is made up of upper and lower insulating sections and an intermediate stem, which latter is surrounded by a coil spring 22, connected at one end to the material of the plug, and having its other end pressing downwardly on the lower section of the plunger. Thus when rupture occurs in the length of the fuse wire, the plunger will be projected downwardly to the signaling position.

In Fig. 18, I have indicated merely a fragment of one of the plungers which engages the fuse wire, and have shown a pulley or anti-friction .roller 25 journaled n the end of the plunger and over which ispassed the fuse wire 8", the said pulley insurmovement of the plunger after rupture of the fuse wire.

- In Fig. 19, I have shown a further rearrangement in which the signal plunger acts through the fuse block instead of through the plug. In this embodiment the plug 6 carries the fuse wire 8? and is formed with a recess 19 across which the fuse wire extends. The signaling plunger 12 extends through the upper end of the fuse block 2 in line with the recess 19* so that the lower end of the plunger rests on the unsupported portion of the fuse wire 8. The plunger may act by gravity, or may be assisted by a" coil spring 26 disposed to thrust the plunger downwardly when the Wire 8 1s ruptured. As long as the fuse wire remains intact the upper end of the plunger l2 Wlll remain exposed, but will drop down out of sight as soon as the fuse wire is-broken, thus.

indicating that the circuit is broken. j

In Fig. 20, 1 have ind cated a further slight modification consisting in providing the usual plug 6 with the usual plunger 12, but the fuse wire arrangement is varied .by having the main fuse wire 8 supported in a groove throughout its length in the plug 6 and not'engaged by the plunger, auxiliary fuse wire 27 preferably of lighter gage, is connected to and arranged parallel with wire 8 and extends across the upper end of plunger 12 for retaining the plunger inits safety position, that isth'e position in dicating that the fuse wire has not been ruptured, which position will be maintained until the wire is broken. Of course, as soon as the main fuse wire is broken, the auxiliary wire will give way, and the plunger will ing against any frictional resistance to the thus be allowed to move to a position indicating the destruction of the fuse.

. What I claim is,

1. In combination, a fuse block, a fuse plug adapted to be thrust longitudinally into the block and to be removable there- 'from, a fuse carried by the plug and extend- I laterally from the bore at the side of the plunger, and the plunger being formed with a recess, and a spring arranged in therecess of the plug and engaging the plug and ex- ,tendinginto the recess in the plunger and movably engaging the plunger for normally exerting pressure against the plunger for pressing the same against the fuse.

3. In combination, a fuse plug formed with a bore, a plunger reciprocably mount-' ed therein, a fuse extending across the bore and engaged by the plunger, the plug being recessed laterally from the bore at opposite sides thereof, and a plate spring 'extending into the lateral recesses of the plug and through the plunger and tensioned to exert pressure against the plunger for-pressing the same against the fuse.

4:. In combination, a fuse plug formed with a bore, a'plunger reciprocably mounted therein, a fuse extending across the bore and engaged by the plunger, the plug being recessed laterally from the bore at opposite sides thereof, and a plate spring extending into the lateral recesses of the plug and through the plunger and tensioned to exert pressure against the plunger for pressing the same against the fuse, the plate spring being arcuate and tensioned to vary the length of its arc for imparting a thrust to the plunger when released.

5. In combination, a fuse plug formed with a bore, a plunger reciprocably mounted therein, a fuse extending across the bore and engaged by the plunger, the plug being recessed laterally from the bore at opposite sides thereof, and a plate spring extending into the lateral recesses of the plug and through the"plunger and tensioned to exert pressureagainst the plunger for pressing vthe same against the fuse, the plate spring being longitudinally arcuate andtensioned for increasing the radius of its are when released for imparting a thrust to the plunger.

6. In combination, a fuse block, a fuse plug adapted to be thrust longitudinally into the block and to be 'movable therefrom, a fuse carried by the plug and extending across the inner end thereof, a signaling plunger extending through the plug and engaging the fuse at the end of the plug, and. means pressing the plunger longitudinally for subjecting the fuse totension.

7. 'In combination, a fuse plug, a reciprocable plunger carried thereby, a fuse carried by the plug and engaging the plunger for retaining the sameagainst reciprocation While the fuse is intact, and a spring extending through the plunger and engaging. the plug and tensioned for. pressing the plunger against the fuse.

8. In combination, a fuse plug, a signaling plunger reciprocably mounted therein, a fuse carried by the plug and disposed to be engaged by the plunger for retaining the plunger against movement while the fuse" is in tact, the plug being formed with a lateral a recess, and a spring extending into the recess and adapted to expand and contract 9Q therein and engaging the plug and plunger and tens'ioned for pressing the plunger against the fuse. p 9. In combination, a fuse plug formed with .a longitudinal, substantially central bore, a reciprocable plunger extending through the bore, a fuse carried by the plug and extending across the end of the plunger for retaining the plunger against movement, the plug beingrecessed laterally from the bore, and a spring operatingin the recess and engaging the plug and plunger for relatively exerting pressure on the plunger toward the fuse the lateral recess being disposed for accommodating operative movements of the spring therein. 10. In combination, a fuse plug formed with a longitudinal, substantially central bore, a reciprocable plunger extending through the bore, a fuse carried by the plug and extending across the end of the Plunger for retaining the plunger against movement, the plug being recessed laterally from the bore at opposlte sides of the plunger, and

cushioning means operating in the recesses and. engaging the plunger for pressingthe same toward the fuse the lateral recess belng disposed for accommodating operative movements of the cushioning means therein.

' In testimony whereof I aflix my signature in presence of two witnesses.

' ROSS LEE BAKER. Witnesses: i i y 

